Quantum Mathematics Seminar: Severin Bunk (Oxford)

MS Teams talk
Wednesday 23rd March 2022 (14:00-15:00)

Robert Laugwitz (organizer)



Quantum Maths Seminar, external speaker:

Speaker: Severin Bunk (University of Oxford)

Title: Higher symmetries of gerbes

Abstract: Gerbes are geometric objects describing the third integer cohomology group of a manifold and the B-field in string theory. Like line bundles, they admit connections and gauge symmetries. In contrast to line bundles, however, there are now isomorphisms between gauge symmetries: the gauge group of a gerbe is a smooth 2-group. Starting from a hands-on example, I will explain gerbes and some of their properties. The main topic of this talk will then be the study of symmetries of gerbes on a manifold with G-action, and how these symmetries assemble into smooth 2-group extensions of G. In the last part, I will survey how this construction can be used to provide a new smooth model for the String group, via a theory of ∞-categorical principal bundles and group extensions.

One hour seminar followed by informal discussion.

School of Mathematical Sciences

The University of Nottingham
University Park
Nottingham, NG7 2RD

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